The lead changed 13 times in a super-charged, sometimes calamitous and incredibly memorable Friday night clash at Allianz Stadium.

Christian Lio-Willie looked to have sealed the game for the Crusaders in the final two minutes of regulation time when he charged over on the short side from a scrum.

The visitors were up 40-37 once Rivez Reihana nailed the conversion from the left side of the park.

But just after the restart, Crusaders winger Johnny McNicholl was ruled to have deliberately knocked on, tapping a Waratahs pass to ground as the hosts were spreading the ball.

McNicholl was shown a yellow card, reducing the Crusaders to 14 players, and giving Harrison the chance to kick for penalty goal.

Crusaders coach Rob Penney was unfazed by the yellow card.

"It's footy. Referees make the call. I thought Nic (Berry, referee) had a good night," he said.

Back-up fly-half Harrison nailed the shot from just inside the halfway line to send an already classic match to golden point.

Three minutes into extra time, Harrison stepped up with his second clutch play, sending the ball over the black dot from the 22 to seal a famous win.

"You spend so much time as a young fella, down the park, dreaming of those moments," Harrison said.

"To get one and put us in the game, to send it to golden point, was special."

The 24-year-old's heroics came in only his third game back from a string of knee injuries that ruled him out for the best part of two years.

"I've spent more time at our facilities than my home in the last 12 months, getting my knee right but also getting my game right," Harrison said.

On the night the Waratahs honoured their champion side of 2014, the win kept the current team's finals equation solvable.

The NSW side has won only two of eight games to begin the year but can likely scrape into the top eight by claiming three of its final six.

"It's been a tough six weeks but it's such a good way to come out of it," said Waratahs coach Darren Coleman.

"We're up and moving now.

"There's a lot of people that like bashing the Waratahs but we go to our bye now happy.

"We can relax and we can come back laser-focused on those last six games."

The Crusaders, meanwhile, fell to a 1-6 record with their second loss to the Waratahs this season but are not out of finals contention.

"We're still growing, we've still got a lot to play for," said Penney.

"We have been struggling to win those clutch moments, which is something we've got to learn and get better at doing."

An expansive first half set the tone for the night and Sevu Reece was in everything for the Crusaders.

The right winger scored the first two tries, the opener coming within a minute, and then set the third up with a break free down the right.

With his double, Reece equalled Caleb Ralph on 52 tries for the Crusaders, the most any man has scored for the Christchurch club.

The 23-22 half-time margin proved a sign of things to come as only a stroke of Harrison's boot separated the sides and snapped the Waratahs' five-game losing streak .

Australian Associated Press